Methods of treating certain depressive disorders and delirium tremens

ABSTRACT

The disclosure provides a method of treating a patient having postpartum depression, premenstrual dysphoric disorder, menopausal depression, or delirium tremens comprising administering an effective amount of an injectable neurosteroid formulation to the patient. In certain embodiments the injectable neurosteroid formulation is an injectable ganaxolone formulation. Two types of injectable neurosteroid formulations may be used in the disclosed methods. The first such formulation is an injectable formulation containing ganaxolone and sulfobutyl ether β-cyclodextrin in a 1:1 inclusion complex. The second such formulation is an injectable neurossteroid formulation comprising a neurosteroid, preferably ganaxolone, but which may be a neurosteroid selected from allopregnanolone, ganaxolone, alphaxalone, alphadolone, hydroxydione, minaxolone, pregnanolone, tetrahydrocorticosterone, and combinations of the foregoing; a surface stabilizer selected from hydroxyl ethyl starch, dextran, and povidone; and a surfactant.

CROSS REFERENCE TO RELATED APPLICATION

The application claims priority from U.S. Provisional Application No.62/385,539 filed Sep. 9, 2016, which is hereby incorporated by referencein its entirety.

BACKGROUND

Postpartum depression is a mood disorder that occurs in some womenfollowing the birth of a child. Common symptoms include feelings ofextreme sadness, loneliness, anxiety, and exhaustion, and mirror thoseof Major Depressive Disorder with the additional criteria that the onsetof symptoms begins within 4 weeks of childbirth. In some cases suffererscan develop psychosis. Rapidly declining postpartum progesterone andallopregnanolone levels are thought to contribute to the development ofpostpartum depression. The CDC estimates between 10-15% of mothersexperience postpartum depression within a year of giving birth, withapproximately 7% of women experiencing postpartum depression withinthree months of delivery. The rates are likely higher in developingcountries. Few women, likely less than 15% seek medical treatment forthe symptoms of postpartum depression. When treated, the most commonlyused medications are Selective Serotonin Reuptake Inhibitors (SSRI's)and Serotonin-norepinephrine Reuptake Inhibitors (SNRI' s), medicationsthan require several weeks to take effect. Allopregnanolone haspreviously been administered as an intravenous infusion to womensuffering from postpartum depression, and found to be stronglyefficacious in placebo-controlled studies. All women in the study weresuffering from postpartum depression and exhibited a Hamilton DepressionRating Scale (HAM-D) baseline score of greater than 25. At the end of asixty hour infusion patients has a mean HAM-D score 12 points lower thanplacebo-treated subjects. The 12 point difference in HAM-D score fromplacebo is larger than the typical 3 to 5 point difference observed inclinical studies for other antidepressants. Allopregnanolone's effectswere also found to be long lasting, persisting 30 days after infusion,although more work needs to be done to understand the duration of theantidepressant effect.

Premenstrual dysphoric disorder (PMDD) is a severe form of premenstrualdisorder, in which a women experiences depressed mood, mood swings,irritability, anxiety, and changes in sleep and appetite as well asdisturbance in functioning at home and/or work prior to menstruation.The Diagnostic and Statistical Manual (DSM-V) provides criteria fordiagnosing PMDD. Symptoms associated with PMDD are confirmed byprospective self-ratings that are tracked for at least two completemenstrual cycles. For diagnosis with PMDD a patient must experience atleast 5 of the listed criteria for two consecutive menstrual cycles.Approximately 3-8% of women of reproductive age experience premenstrualsymptoms severe enough to meet the DMS-V criteria for PMDD. Standard ofcare treatment for PMDD includes SSRIs, which are considered effective,but require several weeks to provide relief The symptoms of PMDD beginsometime after ovulation, but typically around five days before mensesand peak the day before menses or the first day of menses. Symptoms ofPMDD respond to treatment with a serotonin reuptake inhibitor (SRI) evenwhen medication is administered for half of the menstrual cycle (2-4) orat symptom-onset. (5, 6) This is atypical since SRIs require weeks toshow therapeutic activity for a major depressive episode, panic disorderor generalized anxiety disorder. Given the short onset of therapeuticaction of SRIs for PMDD, some hypothesize that SRIs work via a uniquemechanism that enhances the production of neuroactive steroids ratherreuptake blockade of serotonin. Declining levels of allopregnanolone inthe late luteal phase are thought to contribute to PMDD. SSRIs are knownto increase allopregnanolone levels and SSRI administration during thelate luteal phase is known to alleviate PMDD symptoms.

Postmenopausal depression is a form of major depressive disorder (MDD)with considerable unmet medical need; it is often treatment resistant.Approximately 70% of patients do not respond to standard treatment. Only30% of patients with postmenopausal depression achieved remission after8-12 weeks of SSRI therapy. Allopregnanolone levels are inverselycorrelated with the severity of anxiety and depression symptoms in womenacross the weight spectrum. Traditional antidepressants may improvedepression symptoms by increasing allopregnanolone levels.Allopregnanolone levels are known to increase as major depressivedisorder symptoms improve.

Allopregnanolone has been implicated as a treatment for each of thefemale depressive disorders, postpartum depression, premenstrualdysphoric disorder, and treatment resistant postmenopausal depression.However, allopregnanolone has drug properties that reduce itsdesirability as a treatment and limit its utility. Allopregnanolone hasa short half-life and it cannot be administered orally. While infusiontreatment is appropriate for severely depressed patients, many patientswould benefit from a pharmaceutical treatment that could initially beadministered in an injectable form but that could also be orallyadministered for longer term therapy. Thus additional treatments mayeffect improvement through a similar mechanism are desired.

Delirium Tremens (DT) is a severe form of alcohol withdrawal. Onsetoften occurs 48 to 96 hours after the last drink and it marked by arapid onset of acute confusion and profound disorientations. DTsufferers may experience tactile, auditory, and visual hallucinationsand can experience seizures. ICU hospitalization is recommended. Thefirst line of treatment high dose benzodiazepine; propofol and generalanesthesia are administered in refractory cases. Escalating high dosesof phenobarbital have also been used clinically. DT can be fatal and hasa mortality rate of about 0.5 to 1%. In the US there are approximately35,000 cases of DT annually with an aggregate cost of treatment ofapproximately $375 million. There are currently no FDA approved drugsfor treating DT and there are no reports of any being developed.Improved treatments for DT that can result in faster recovery, shortenthe duration of inpatient hospitalization, and reduce the time of ICUtreatment.

SUMMARY

The disclosure provides a method of treating a patient having postpartumdepression, premenstrual dysphoric disorder, postmenopausal depression,or delirium tremens comprising administering an effective amount of aninjectable neurosteroid formulation to the patient; wherein theinjectable neurosteroid formulation is an injectable ganaxoloneformulation.

This disclosure includes methods of treating postpartum depression,premenstrual dysphoric disorder, postmenopausal depression, and deliriumtremens with two types of injectable neurosteroid formulations. Thefirst such formulation is an injectable formulation containingganaxolone and sulfobutyl ether β-cyclodextrin in a 1:1 inclusioncomplex. The second such formulation is an injectable neurosteroidformulation comprising a neurosteroid, preferably ganaxolone, but whichmay be a neurosteroid selected from allopregnanolone, ganaxolone,alphaxalone, alphadolone, hydroxydione, minaxolone, pregnanolone,tetrahydrocorticosterone, and combinations of the foregoing; a surfacestabilizer such as hydroxyl ethyl starch, dextran, and povidone; and asurfactant. This formulation may also contain sucrose to avoid particleagglomeration.

DETAILED DESCRIPTION

Definitions

Recitation of ranges of values are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. The endpoints of all ranges are includedwithin the range and independently combinable. All methods describedherein can be performed in a suitable order unless otherwise indicatedherein or otherwise clearly contradicted by context. The use of any andall examples, or exemplary language (e.g., “such as”), is intendedmerely for illustration and does not pose a limitation on the scope ofthe invention unless otherwise claimed. No language in the specificationshould be construed as indicating any non-claimed element as essentialto the practice of the invention.

The terms “a” and “an” do not denote a limitation of quantity, butrather denote the presence of at least one of the referenced item.

The term “about” is used synonymously with the term “approximately.” Asone of ordinary skill in the art would understand, the exact boundary of“about” will depend on the component of the composition. Illustratively,the use of the term “about” indicates that values slightly outside thecited values, i.e., plus or minus 0.1% to 10%, which are also effectiveand safe. Thus compositions slightly outside the cited ranges are alsoencompassed by the scope of the present claims.

An “active agent” is any compound, element, or mixture that whenadministered to a patient alone or in combination with another agentconfers, directly or indirectly, a physiological effect on the patient.When the active agent is a compound, salts, solvates (includinghydrates) of the free compound or salt, crystalline and non-crystallineforms, as well as various polymorphs of the compound are included.Compounds may contain one or more asymmetric elements such asstereogenic centers, stereogenic axes and the like, e.g. asymmetriccarbon atoms, so that the compounds can exist in differentstereoisomeric forms. These compounds can be, for example, racemates oroptically active forms. For compounds with two or more asymmetricelements, these compounds can additionally be mixtures of diastereomers.For compounds having asymmetric centers, it should be understood thatall of the optical isomers in pure form and mixtures thereof areencompassed. In addition, compounds with carbon-carbon double bonds mayoccur in Z- and E-forms, with all isomeric forms of the compounds beingincluded in the present invention. In these situations, the singleenantiomers, i.e. optically active forms, can be obtained by asymmetricsynthesis, synthesis from optically pure precursors, or by resolution ofthe racemates. Resolution of the racemates can also be accomplished, forexample, by conventional methods such as crystallization in the presenceof a resolving agent, or chromatography, using, for example a chiralHPLC column.

The terms “comprising,” “including,” and “containing” are non-limiting.Other non-recited elements may be present in embodiments claimed bythese transitional phrases. Where “comprising,” “containing,” or“including” are used as transitional phrases other elements may beincluded and still form an embodiment within the scope of the claim. Theopen-ended transitional phrase “comprising” encompasses the intermediatetransitional phrase “consisting essentially of” and the close-endedphrase “consisting of”

A “bolus dose” is a relatively large dose of medication administered ina short period, for example within 1 to 30 minutes.

C_(max) is the measured concentration of an active concentration in theplasma at the point of maximum concentration.

The term “inclusion complex” is intended to mean a complex between aganaxolone molecule and a cyclodextrin molecule. A molecule ofganaxolone may be partially inserted into the hydrophobic cavity of onecyclodextrin molecule. In certain non-limiting embodiments the inclusioncomplex has one ganaxolone molecule and one sulfobutylether-β-cyclodextrin molecule, to give a 1:1 ratio between ganaxoloneand sulfobutyl ether-β-cyclodextrin.

Infusion administration is a non-oral administration, typicallyintravenous though other non-oral routes such as epidural administrationare included in some embodiments. Infusion administration occurs over alonger period than a bolus administration, for example over a period ofat least 15 minutes, at least 30 minutes, at least 1 hour, at least 2hours, at least 3 hours, or at least 4 hours.

A “patient” in the context of this disclosure is a human or other mammalin need of medical treatment.

A “therapeutically effective amount” or “effective amount” is thatamount of a pharmaceutical agent to achieve a pharmacological effect.The term “therapeutically effective amount” includes, for example, aprophylactically effective amount, that is an amount effective tosignificantly reduce the probability of occurrence of a disorder in apatient at risk for the disorder. An “effective amount” of neurosteroidis an amount needed to achieve a desired pharmacologic effect ortherapeutic improvement without undue adverse side effects. Theeffective amount of neurosteroid will be selected by those skilled inthe art depending on the particular patient and the disorder. It isunderstood that “an effective amount” or “a therapeutically effectiveamount” can vary from patient to patient, due to variation in metabolismof neurosteroid, age, weight, general condition of the subject, thecondition being treated, the severity of the condition being treated,and the judgment of the prescribing physician. When discussing a methodof treating depression, an effective amount includes an amount effectiveto have a statistically significant and favorable effect on thepatient's score on a depression symptoms rating scale. A “Depressionsymptoms rating scale” refers to any one of a number of standardizedquestionnaires, clinical instruments, or symptom inventories utilized tomeasure symptoms and symptom severity in depression. Such rating scalesare often used in clinical studies to define treatment outcomes, basedon changes from the study's entry point(s) to endpoint(s). Suchdepression symptoms rating scales include, but are not limited to, the17 item Hamilton Rating Scale for Depression (HAM-D-17 or HRSD₁₇), the30-Item Inventory of Depressive Symptomatology (IDS-C₃₀), TheMontgomery-Asperg Depression Rating Scale (MADRS), the Daily Recordingof Severity of Problems (DRSP), and the Inventory of DepressiveSymptomatology (IDS). Such ratings scales may involve patientself-report or be clinician rated. A 50% or greater reduction in adepression ratings scale score over the course of a clinical trial(starting point to endpoint) is typically considered a favorableresponse for most depression symptoms rating scales. “Remission” inclinical studies of depression often refers to achieving at, or below, aparticular numerical rating score on a depression symptoms rating scale(for instance, less than or equal to 7 on the 17 question HRSD₁₇; orless than or equal to 5 on the QIDS-SR₁₆; or less than or equal to 10 onthe MADRS).

When discussing a method of treating premenstrual dysphoric disorder(PMDD), an effective amount includes an amount effective to have astatistically significant and favorable effect on the patient's score ona depression symptom rating scale, for example the DRSP or IDS. Aneffective amount of neurosteroid for use in the method of treating PMDDalso includes an amount effective to have a statistically significantand favorable effect on the patient's score on the Scale of PremenstrualTension Syndrome (PMTS).

“Treat” or “treatment” refers to any treatment of a disorder or disease,such as inhibiting the disorder or disease, e.g., arresting thedevelopment of the disorder or disease, relieving the disorder ordisease, causing regression of the disorder or disease, relieving acondition caused by the disease or disorder, or reducing the symptoms ofthe disease or disorder. In certain embodiments “treatment” includesprophylactic treatment, that is administering an amount of neurosteroideffective to significantly reduce the probability of occurrence of adisorder or symptoms of a disorder.

Chemical Description

Ganaxolone (CAS Reg. No. 38398-32-2, 3α-hydroxy,3β-methyl-5α-pregnan-20-one) is a synthetic steroid with anti-convulsantactivity useful in treating epilepsy and other central nervous systemdisorders.

Ganaxolone has a relatively long half-life-approximately 20 hours inhuman plasma following oral administration (Nohria, V. and Giller, E.,Neurotherapeutics, (2007) 4(1): 102-105). Furthermore, ganaxolone has ashort T_(max), which means that therapeutic blood levels are reachedquickly. Thus initial bolus doses (loading doses) may not be required,which represents an advantage over other anti-depressant or alcoholwithdrawal treatments. Ganaxolone is useful for treating seizures inadult and pediatric epileptic patients.

Allopregnanolone (CAS Reg. No. 516-54-1, 3 α, 5α-tetrahydroprogesterone)is an endogenous progesterone derivative with anti-convulsant activity.

Allopregnanolone has a relatively short half-life, about 45 minutes inhuman plasma.

Alphaxalone, also known as alfaxalone, (CAS Reg. No. 23930-19-0,3α-hydroxy-5α-pregnan-11,20-dione) is a neurosteroid with an anestheticactivity. An injectable nanoparticle neurosteroid dosage form containingalphaxalone alone or in combination with either ganaxolone orallopregnanolone is within the scope of this disclosure.

Alphadolone, also known as alfadolone, (CAS Reg. No. 14107-37-0, 3α,21-dihydroxy-5α-pregnan-11,20-dione) is a neurosteroid with anestheticproperties.

Additional neurosteroids that may be used in the injectable nanoparticleneurosteroid formulation of this disclosure include formulations includehydroxydione (CAS Reg. No. 303-01-5,(5β)-21-hydroxypregnane-3,20-dione), minaxolone (CAS Reg. No.62571-87-3,2β,3α,5α,11α)-11-(dimethylamino)-2-ethoxy-3-hydroxypregnan-20-one),pregnanolone (CAS Reg. No. 128-20-1, (3α,5β)-d-hydroxypreganan-20-one),renanolone (CAS Reg. No. 565-99-1, 3α-hydroxy-5β-pregnan-11,20-dione),or tetrahydrocorticosterone (CAS Reg. No. 68-42-8,3α,5α-pregnan-20-dione).

This disclosure includes methods of treating postpartum depression,premenstrual dysphoric disorder, postmenopausal depression, and deliriumtremens with two types of injectable neurosteroid formulations. Thefirst such formulation is an injectable formulation containingganaxolone and sulfobutyl ether β-cyclodextrin in a 1:1 inclusioncomplex. The second such formulation is an injectable neurosteroidformulation comprising a neurosteroid selected from allopregnanolone,ganaxolone, alphaxalone, alphadolone, hydroxydione, minaxolone,pregnanolone, tetrahydrocorticosterone, and combinations of theforegoing; a surface stabilizer, preferably selected from hydroxyl ethylstarch, dextran, and povidone; and a surfactant.

Injectable Substituted Beta-Cyclodextrin-Ganaxolone Formulations

U.S. Pat. Nos. 5,134,127 and 5,376,645 each to Stella et al. disclosesulfoalkyl ether cyclodextrin derivatives and their use as solubilizingagents for water-insoluble drugs for oral, intranasal or parenteraladministration including intravenous and intramuscular administration.Stella et al. disclose an inclusion complex of the water-insoluble drugand the sulfoalkyl ether cyclodextrin derivative, and pharmaceuticalcompositions containing these inclusion complexes. Examples ofsulfoalkyl ether cyclodextrin derivatives disclosed includemono-sulfobutyl ethers of β-cyclodextrin and monosulfopropyl ethers ofβ-cyclodextrin. CAPTISOL, marketed by Ligand Pharmaceuticals is asulfobutyl ether β-cyclodextrin with an average 6-7 sulfobutyl ethergroups per cyclodextrin molecule. CAPTISOL is sold as an amorphousmaterial and has an average molecular weight of 2163 g/ mole based on6.5 substitutions per molecule.

The disclosure provides injectable substituted β-cyclodextrin ganaxoloneformulations, including formulations containing CAPTISOL-ganaxoloneinclusion complexes. Injectable substituted β-cyclodextrin ganaxoloneformulations disclosed herein include formulations suitable forintramuscular, intravenous, intraarterial, intraspinal, and intrathecalinjection. Injectable formulations include parenteral formulationssuitable for intravenous infusion. Suitable injectable substitutedβ-cyclodextrin -ganaxolone formulations for use in the methods of thisdisclosure include formulations disclosed in U.S. Ser. No. 15/276,203and U.S. Ser. No. 15/018,258 both of which are hereby incorporated byreference in their entirety.

The disclosure provides methods of using injectable substitutedβ-cyclodextrin ganaxolone formulations containing an inclusion complexof a substituted-β-cyclodextrin, such as CAPTISOL, and ganaxolone, and apharmaceutically acceptable carrier. In certain embodiments thesubstituted β-cyclodextrin ganaxolone formulation of the disclosure willbe in the form of an aqueous parenteral or injectable formulation.

Ganaxolone is very poorly soluble in water (<0.001 mg/mL) and thus isdifficult to formulate as an aqueous injectable. The inventors havefound that the water-solubility of ganaxolone may be sufficientlyincreased to allow it to be formulated as an aqueous injectable bycomplexing ganaxolone with a substituted β-cyclodextrin, such asCAPTISOL. In effect, the substituted β-cyclodextrin inhibitsprecipitation of the ganaxolone at the injection site, providing reducedirritation and permitting injection without unacceptable injection-siteirritation.

The disclosure provides methods of using injectable substitutedβ-cyclodextrin ganaxolone formulations containing ganaxolone at aconcentration of 0.25 mg/mL, 0.5 mg/mL, 1.0 mg/mL, 1.5 mg/mL, 2.0 mg/mL,2.5 mg/mL, 3.0 mg/mL, 3.5 mg/mL, 4.0 mg/mL, 4.5 mg/mL. 5.0 mg/mL, 5.5mg/mL, 6.0 mg/mL, 6.5 mg/mL, 7.0 mg/mL, 7.5 mg/mL, 8.0 mg/mL, 8.5 mg/mL, 9.0 mg/mL, 10 mg/mL, 11 mg/ mL, 12 mg/mL, 13 mg/mL, or about 15mg/mL. All ranges including any two of the foregoing concentrations ofsubstituted β-cyclodextrin as endpoints are also included in thedisclosure. For example, the disclosure includes methods usingsubstituted β-cyclodextrin ganaxolone formulations containing from about0.5mg/mL, to about 15 mg/mL, about 1.0 mg/mL to about 10 mg/mL, about2.0 mg/mL to about 8.0 mg/mL, or about 4.0 mg/mL to about 8.0 mg/mgganaxolone. An embodiment comprising a method of using an aqueousinjectable ganaxolone/sulfobutyl ether β-cyclodextrm formulation (e.g.in an inclusion complex) and containing from about 2.0 mg/mL, to about8.0 mg/mL ganaxolone is included in this disclosure.

The substituted β-cyclodextrin used in the methods of this disclosurewill be in a weight: weight ratio to ganaxolone of about 10:1 to 100: 1,or about 40:1 to about 80:1, or about 52:1 to about 80:1, or about 52:1to about 85:1, or about 55:1 to about 70:1, or about 55:1 to about 65:1or about 55:1. The ratio of substituted β-cyclodextrin to ganaxoloneneeded to inhibit or prevent precipitation of ganaxolone in theformulation or upon injection depends on the particular type ofsubstituted-β-cyclodextrin used. When CAPTISOL is used aCAPTISOL:ganaxolone ratio of about 52:1 to about 85:1, or about 55:1 toabout 70:1, or about 55:1 to about 65:1 or about 55:1 is required. Thesubstituted β-cyclodextrin may be present in an amount greater than thatneeded to complex the ganaxolone to aid in ganaxolone solubilization.

In methods disclosed herein the ganaxolone and sulfobutylether-β-cyclodextrin may be in an inclusion complex, and the inclusioncomplex may be a 1:1 ganaxolone: sulfobutyl ether-β-cyclodextrincomplex.

In certain embodiments the ganaxolone and sulfobutylether-β-cyclodextrin inclusion complex provides at least 2.0 mg/mLganaxolone (or at least 0.1 mg/mL, or at least 1.0 mg/mL, or at least11.5 mg/ mL), when the amount of ganaxolone provided by the complex ismeasured at a sulfobutyl ether-β-cyclodextrin concentration of 30% w/vin water. In certain embodiments the ganaxolone concentration is about0.1 mg/ml to about 15 mg/ml, or about 1 mg/ml to about 10 mg/ml, orabout 1 mg/ml to about 5 mg/ml.

In certain embodiments ganaxolone will be present in the aqueousinjectable formulation in an amount of from about 0.1 to about 5% byweight, or from about 0.2 to about 2.5%, or from about 0.5 to about 1.5%by weight based on the total injectable formulation weight.

The disclosure also provides methods in which the injectable substitutedβ-cyclodextrin ganaxolone formulations containing substitutedβ-cyclodextrin at a concentration of 5mg/mL, 10 mg/mL, 50 mg/mL, 100mg/mL, 150 mg/mL, 200 mg/mg/mL, 250 mg/mL, 300 mg/mL, 350 mg/ mL, 400mg/mL, 450 mg/mL, 500 mg/mL, 550 mg/mL, 600 mg/mL, 650 mg/mL, or 700mg/mL so long as the ratio of substituted β-cyclodextrin to ganaxoloneis about 52:1 or greater. All ranges including any two of the foregoingconcentrations of substituted β-cyclodextrin as endpoints are alsoincluded in the disclosure. For example, the disclosure includessubstituted β-cyclodextrin ganaxolone formulations containing from about5 mg/mL to about 500 mg/mL, or about 50 mg/mL to about 500 mg/mL, orabout 100 mg/mL to about 400 mg/mL substituted β-cyclodextrin. Thedisclosure includes an embodiment in which the substitutedβ-cyclodextrin ganaxolone formulations contain from about 25 mg/mL toabout 400 mg/mL sulfobutyl ether-β-cyclodextrin.

Ganaxolone will form a complex with substituted-β-cyclodextrin whichcomplex may be dissolved in water to form an injectable formulation.However, physical mixtures of ganaxolone and substituted-β-cyclodextrinare within the scope of the disclosure.

The disclosure includes methods in which the ganaxolone-sulfobutylether-β-cyclodextrin formulation additionally comprises a buffer, suchas an acetate, citrate, tartrate, phosphate, or triethanolamine (TRIS)buffer an acid or base buffer to adjust pH to desired levels. In someembodiments the desired pH is 2.5-11.0, 3.5-9.0, or 5.0-8.0, or 6.0-8.0,or 6.8-7.6, or 6.80-7.10, or about 7.4. Examples of acid buffers usefulin the substituted β-cyclodextrin-ganaxolone formulation include oxalicacid, maleic acid, fumaric acid, lactic acid, malic acid, tartaric acid,citric acid, benzoic acid, acetic acid, methanesulfonic acid, histidine,succinic acid, toluenesulfonic acid, benzenesulfonic acid,ethanesulfonic acid and the like. Acid salts of the above acids may beemployed as well. Examples of base buffers useful in the formulationinclude carbonic acid and bicarbonate systems such as sodium carbonateand sodium bicarbonate, and phosphate buffer systems, such as sodiummonohydrogen phosphate and sodium dihydrogen phosphate. In certainembodiments the buffer is a phosphate buffer. In certain embodiments thebuffer is phosphate buffered saline. In certain embodiments the bufferis a mixture of monobasic and dibasic phosphate buffers, such aspotassium phosphate mono or dibasic phosphate buffers. The concentrationof each component of a phosphate buffer system will be from about 5 mMto about 20 mM, about 10 mM to about 200 mM, or from about 20 mM toabout 150 mM, or from about 50 mM to about 100 mM.

The disclosure includes embodiments in which the of the ganaxolone-sulfobutyl ether-β-cyclodextrin formulation is about 6.9, 7.0, 7.1,7.2, 7.3, or 7.4.

The disclosure includes methods in which the formulation containselectrolytes, such as sodium or potassium and in which the formulationis from about 0.5% to about 1.5% sodium chloride (saline).

The disclosure includes methods in which the formulation containstonicity adjusting agents so that it is isotonic with human plasma.Examples of tonicity adjusting agents useful in the formulation include,but are not limited to, dextrose, mannitol, sodium chloride, orglycerin. In certain embodiments the tonicity agent is 0.9% sodiumchloride.

The substituted cyclodextrin-ganaxolone injectable formulation used inthe methods of this disclosure may contain a non-aqueous carrier.Non-aqueous carriers include any pharmaceutically acceptable excipientcompatible with ganaxolone and capable of providing the desiredpharmacological release profile for the dosage form. Carrier materialsinclude, for example, suspending agents, surfactants, solubilizers,stabilizers, lubricants, wetting agents, diluents, and the like.“Pharmaceutically compatible carrier materials” may comprise, but arenot limited to, acacia, gelatin, colloidal silicon dioxide, calciumglycerophosphate, calcium lactate, maltodextrin, glycerin, magnesiumsilicate, polyvinylpyrrolidone (PVP), cholesterol, cholesterol esters,sodium caseinate, soy lecithin, taurocholic acid, phosphotidylcholine,sodium chloride, tricalcium phosphate, dipotassium phosphate, celluloseand cellulose conjugates, sugars sodium stearoyl lactylate, carrageenan,monoglyceride, diglyceride, pregelatinized starch, and the like.

The substituted β-cyclodextrin-ganaxolone injectable formulation mayalso contain a non-aqueous diluent such as ethanol, one or more polyol(e.g glycerol, propylene glycol), an oil carrier, or any combination ofthe foregoing.

The substituted β-cyclodextrin-ganaxolone injectable formulation of themay additionally comprise a preservative. The preservative may be usedto inhibit bacterial growth. Preservatives suitable for parenteralformulations include benzyl alcohol, chlorbutanol, 2-ethoxyethanol,parabens (methyl, ethyl, propyl, butyl, and combinations), benzoic acid,sorbic acid, chlorhexidene, phenol, 3-cresol, thimerosal, andphenylmercurate salts.

The substituted β-cyclodextrin-ganaxolone injectable formulation mayoptionally include a coating or surfactant to insure desirablesolubilization and fluidity of ganaxolone in the substitutedβ-cyclodextrin, such as CAPTISOL.

Surfactants include compounds such as lecithin (phosphatides); sorbitantrioleate and other sorbitan esters; polyoxyethylene sorbitan fatty acidesters (e.g., the commercially available TWEENS such as polyoxyethylenesorbitan monolaurate (TWEEN 20, also known as Polysorbate 20, CAS Reg.No. 9005-64-5) and polyoxyethylene sorbitan monooleate (TWEEN 80, ICISpeciality Chemicals, also known as Polysorbate 80 (CAS Reg. No.9005-65-6)); poloxamers (e.g., poloxamer 188 (PLURONIC F68) andpoloxamer 338 (PLURONIC F108), which are block copolymers of ethyleneoxide and propylene oxide, and poloxamer 407, which is a triblockcopolymer of propylene glycol and two blocks of polyethylene glycol);sodium cholesterol sulfate or other cholesterol salts; and bile salts,such as sodium deoxycholate, sodium cholate, sodium glycholate, salts ofdeoxycholic acid, salts of glycholic acid, salts of chenodeoxycholicacid, and salts of lithocholic acid.

The substituted β-cyclodextrin-ganaxolone injectable formulation maycomprise a substituted β-cyclodextrin-ganaxolone injectable formulationcontaining (1) ganaxolone, from 2 to about 8 mg/mL, (2) CAPTISOL, fromabout 100 to about 400 mg/mL, (3) phosphate buffer to adjust to fromabout 7.0 to about 7.5, and (4) water. The β-cyclodextrin-ganaxoloneinjectable formulation may be aseptically filtered, for example, througha 0.2 μm membrane filter. The β-cyclodextrin-ganaxolone injectableformulation may be autoclaved or lyophilized for storage andreconstitution.

The disclosure includes any β-cyclodextrin-ganaxolone injectableformulation as described in this disclosure that also meet the followingrequirements. Any of the following requirements can he combined so longas a stable formulation results. In any of the disclosed injectableβ-cyclodextrin-ganaxolone injectable formulations, the ganaxolone andthe sulfobutyl ether-β-cyclodextrin are in the form of an inclusioncomplex.

(a) The β-cyclodextrin-ganaxolone injectable formulation includes asurfactant and the surfactant is a sorbitan ester, sodium deoxycholoate,a polyoxyethylene sorbitan fatty acid ester, a poloxamer, a cholesterolsalt, or a bile salt.

(b) The β-cyclodextrin-ganaxolone injectable formulation is about 0.05to about 15 weight percent surfactants.

(c) The β-cyclodextrin-ganaxolone injectable formulation includes asurfactant wherein the surfactant is polysorbate 80.

(d) The β-cyclodextrin-ganaxolone injectable formulation includes abuffer.

(e) The β-cyclodextrin-ganaxolone injectable formulation includes abuffer having a pH of about 6.8 to about 7.6.

(f) The β-cyclodextrin-ganaxolone injectable formulation includes aphosphate buffer. In certain embodiments the phosphate buffer isphosphate buffered saline. The buffer is a combination of a monobasicphosphate buffer and a dibasic phosphate buffer, wherein theconcentration of each phosphate buffer is 2 mM to 50 mM. In certainembodiments the phosphate buffer is a combination of a monobasicphosphate buffer and a dibasic phosphate buffer, wherein theconcentration of each phosphate buffer is 2 mM to 50 mM.

(g) The β-cyclodextrin-ganaxolone injectable formulation includes aconcentration of ganaxolone that is 2 mg/ml to 8 mg/ml; the w/w ratio ofsulfobutyl ether-β-cyclodextrin to ganaxolone is within the range fromabout 52:1 to about 90:1, or about 52:1 to about 80:1, or about 55:1 toabout 70:1; or at least 55:1; the formulation contains a buffer and hasa pH of 6.7 to 7.3; and the formulation contains from 0.5 to 15 weightpercent surfactant, or about 1 to about 10 weight percent surfactant; orabout 10 weight percent surfactant.

(h) The sulfobutyl ether β-cyclodextrin-ganaxolone injectableformulation includes a concentration of ganaxolone that is from 1 mg/mlto 5 mg/ml; the weight percent of sulfobutyl ether-β-cyclodextrin 20% to40%; or 25% to 35%, or about 30% sulfobutyl ether β-cyclodextrin and theformulation contains from 5% to 20%; 5% to 15%; or about 10% (weightpercent) of at least one of the following: a surfactant, ethanol,glycerin or propylene glycol. In certain embodiments this formulationmay contain a surfactant chosen from lecithin (phosphatides); sorbitantrioleate and other sorbitan esters; polyoxyethylene sorbitan fatty acidesters (e.g., the commercially available TWEENS such as polyoxyethylenesorbitan monolaurate and polyoxyethylene sorbitan monooleate; poloxamers(e.g., poloxamer 188 (PLURONIC F68) and poloxamer 338 (PLURONIC F108),which are block copolymers of ethylene oxide and propylene oxide, andpoloxamer 407, which is a triblock copolymer of propylene glycol and twoblocks of polyethylene glycol); sodium cholesterol sulfate or othercholesterol salts; and bile salts

(i) The β-cyclodextrin-ganaxolone injectable formulation includes apreservative. In certain embodiments the preservative is benzyl alcohol,chlorbutanol, 2-ethoxyethanol, parabens (including methyl, ethyl,propyl, butyl, and combinations), benzoic acid, sorbic acid,chlorhexidene, phenol 3-cresol, thimerosal, or a phenylmercurate salt.

(j) The sulfobutyl ether-β-cyclodextrin are in the form of an inclusioncomplex, wherein the inclusion complex provides at least 2.0 mg/mLganaxolone, when the amount of ganaxolone provided by the complex ismeasured at a sulfobutyl ether-β-cyclodextrin concentration of about 30%w/v in water.

(k) The β-cyclodextrin-ganaxolone injectable formulation includesethanol, e.g. 1 to 20 percent (volume/volume). 5 to 15 percent (v/v), orabout 10 percent ethanol (v/v).

(I) The β-cyclodextrin-ganaxolone injectable formulation includes awetting agent. In certain embodiments the solubilizing agent is glycerinor propylene glycol, e.g. 1 to 20 percent (volume/volume), 5 to 15percent (v/v), or about 10 percent (v/v).

Injectable Neurosteroid Nanoparticle Formulations

This disclosure includes methods of using injectable nanoparticleformulations, including formulations suitable for intravenousadministration. The neurosteroid nanoparticles contain a neurosteroid, asurface stabilizer, (such as a polymeric surface stabilizer, for examplehydroxyl ethyl starch, dextran, lecithin, Poloxamer 188, Polysorbate 80,or povidone) and a surfactant. In certain embodiments the neurosteroid,may be ganaxolone or allopregnanolone.

The injectable neurosteroid nanoparticle formulations, includingformulations containing nanoparticles comprising a neurosteroid, asurface stabilizer, such as either hydroxyethyl starch or dextran, and asurfactant. In certain embodiments the nanoparticles comprise ganaxoloneor allopregnanolone, hydroxyethyl starch, and a surfactant. Injectableneurosteroid nanoparticle formulations disclosed herein includeformulations suitable for intramuscular, intravenous, intraarterial,intraspinal, subcutaneous, and intrathecal injection. Injectableformulations include parenteral formulations suitable for intravenousinfusion.

In certain embodiment the surface stabilizer is a blood replacer, suchas a blood volume expander. In certain embodiments the surfacestabilizer is either hydroxyethyl starch, dextran, or povidone.Hydroxyethyl starch is used as a blood volume expander in patientssuffering from severe blood loss. Grades of hydroxyethyl starch suitablefor use in the neurosteroid nanoparticles include 130/0.4 (CAS Reg. No.9005-27-0). In certain embodiments the surface stabilizer is dextran.Dextran is a single chain branched glucan having chains of varyinglengths. Like hydroxyethyl starch, dextran is also used as a bloodvolume expander. Dextrans are classified according to MW. Dextranshaving molecular weights from 40 kD to 75 kD have been used as bloodvolume expanders. Suitable dextrans for intravenous use include Dextran40, Dextran 60, Dextran 70, and Dextran 75. In certain embodiments thesurface stabilizer is a dextran having a molecular weight from about 40kD to about 75 kD. In certain embodiments the surface stabilizer isDextran 70. Povidone, also known as polyvinylpyrrolidone, is anotherapproved plasma expander. Low molecular weight polyvinylpyrrolidone(C12-C17) is another approved excipient that may be used in intravenousdrug products. Other excipients useful as surface stabilizers for theinjectable neurosteroid nanoparticle formulation include human serumalbumin, hydrolyzed gelatin, polyoxyethylene castor oil, andpolyoxyethylene hydrogenated castor oil. Suitable injectable ganaxolonenanoparticle formulations for use in the methods of this disclosureinclude formulations disclosed in U.S. Ser. No. 15/294,135 which ishereby incorporated by reference in its entirety.

The weight to weight ratio of neurosteroid to surface stabilizer isabout 10:1 to 0.5: 1, or about 5:1 to about 0.5:1, or about 4:1 to about1:1, or about 3.5:1 to about 3:1, or about 3.3:1.

The injectable neurosteroid nanoparticle injectable formulation includesa surfactant. Surfactants suitable for use in the neurosteroidnanoparticle formulations include compounds such as lecithin(phosphatides), sorbitan trioleate and other sorbitan esters,polyoxyethylene sorbitan fatty acid esters (e.g., the commerciallyavailable TWEENS such as polyoxyethylene sorbitan monolaurate (TWEEN 20)and polyoxyethylene sorbitan monooleate (TWEEN 80) (ICI SpecialityChemicals)); poloxamers (e.g., poloxamer 188 PLURONIC F68 and poloxamer338 (PLURONIC F108), which are block copolymers of ethylene oxide andpropylene oxide), lecithin, sodium cholesterol sulfate or othercholesterol salts, and bile salts, such as sodium deoxycholate.Additional bile salts that may be used as surfactants include sodiumcholate, sodium glycholate, salts of deoxycholic acid, salts ofglycholic acid, salts of chenodeoxycholic acid, and salts of lithocholicacid.

The injectable neurosteroid nanoparticle formulations may also includean acid or base buffer to adjust pH to desired levels. In someembodiments the desired pH is 2.5-11.0, 3.5-9.0, or 5.0-8.0, or 6.0-8.0,or 7.0-7.6, or about 7.4. Examples of acid buffers useful in theinjectable neurosteroid nanoparticle formulation include oxalic acid,maleic acid, fumaric acid, lactic acid, malic acid, tartaric acid,citric acid, benzoic acid, acetic acid, methanesulfonic acid, histidine,succinic acid, toluenesulfonic acid, benzenesulfonic acid,ethanesulfonic acid and the like. Acid salts of the above acids may beemployed as well. Examples of base buffers useful in the formulationinclude carbonic acid and bicarbonate systems such as sodium carbonateand sodium bicarbonate, and phosphate buffer systems, such as sodiummonohydrogen phosphate and sodium dihydrogen phosphate. In certainembodiments the buffer is a phosphate buffer. In certain embodiments thebuffer is phosphate buffered saline. The concentration of each componentof a phosphate buffer system will be from about 10 mM to about 200 mM,or from about 20 mM to about 150 mM, or from about 50 mM to about 100mM.

The disclosure includes embodiments in which the pH of the neurosteroidnanoparticle formulation is about 7.4.

The formulation may contain electrolytes, such as sodium or potassium.The disclosure includes embodiments in which the formulation is fromabout 0.5% to about 1.5% sodium chloride (saline).

The formulation may contain tonicity adjusting agents so that it isisotonic with human plasma. Examples of tonicity adjusting agents usefulin the formulation include, but are not limited to, dextrose, mannitol,sodium chloride, or glycerin. In certain embodiments the tonicity agentis 0.9% sodium chloride.

The injectable neurosteroid nanoparticle formulation may include anantifoaming agent. Suitable antifoaming agents include dimethicone,myristic acid, palmitic acid, and simethicone.

The injectable neurosteroid nanoparticle formulation used in thedisclosed methods can also contain a non-aqueous diluent such asethanol, one or more polyol (e.g. glycerol, propylene glycol), an oilcarrier, or any combination of the foregoing.

The injectable neurosteroid nanoparticle formulation used in thedisclosed methods can additionally comprise a preservative. Thepreservative may be used to inhibit bacterial growth or preventdeterioration of the active agent. Preservatives suitable for parenteralformulations include ascorbic acid, acetylcysteine, benzalkoniumchloride, benzethonium chloride, benzoic acid, benzyl alcohol,chlorbutanol, chlorhexidene, m-cresol, 2-ethoxyethanol, human serumalbumin, monothioglycerol, parabens (methyl, ethyl, propyl, butyl, andcombinations), phenol, phenylmercurate salts (acetate, borate nitrate),sorbic acid, sulfurous acid salts (bisulfite and metabisulfite), andthimerosal. In certain embodiments the preservative is an antioxidantssuch ascorbic acid, glutathione, or an amino acid. Amino acids useful asantioxidants include methionine, cysteine, and L-arginine.

The injectable neurosteroid nanoparticle formulations may contain anyadditional pharmaceutically acceptable excipient compatible with theneurosteroid and capable of providing the desired pharmacologicalrelease profile for the dosage form. Additional excipients include, forexample, suspending agents, solubilizers, stabilizers, lubricants,wetting agents, and the like. Pharmaceutically acceptable excipients maycomprise, but are not limited to, acacia, gelatin, colloidal silicondioxide, calcium glycerophosphate, calcium lactate, maltodextrin,glycerin, magnesium silicate, polyvinylpyrrolidone (PVP), cholesterol,cholesterol esters, sodium caseinate, soy lecithin, taurocholic acid,phosphotidylcholine, sodium chloride, tricalcium phosphate, dipotassiumphosphate, cellulose and cellulose conjugates, sugars sodium stearoyllactylate, carrageenan, monoglyceride, diglyceride, pregelatinizedstarch, and the like.

Neurosteroid nanoparticles have a volume weighted median diameter (D50)of from about 10 to about 2000 nm, from about 10 nm to about 350 nm, orhaving a D50 of from about 50 nm to about 300 nm, or having a D50 offrom about 100 nm to about 250 nm, or having a D50 of about 150 nm toabout 220 nm, or having a D50 of less than 350 nm, less than 300 nm,less than 250 nm, or less than 200 nm.

In one aspect the neurosteroid nanoparticles have at least one of thefollowing properties: (a) greater than 90% of the neurosteroid by weightis in the form of submicron particle having an effective size of about50 nm to about 250 nm; (b) at least about 20% of the neurosteroid byweight is in the form of an amorphous powder; (c) at least about 50% ofthe neurosteroid by weight is in the form of a crystalline powder of asingle polymorph; (d) at least about 50% of the neurosteroid is in theform of a semi-crystalline powder; (e) the neurosteroid is in the formof particles wherein at least about 50%, or at least 60%, or at least70%, or at least 80%, or at least 90% of the particles by weight have aneffective size less than 300 nm; (f) the neurosteroid is in the form ofparticles wherein at least about 50% of the particles by weight have andeffective size less than 250 nm; (g) the neurosteroid is in the form ofparticles having a D50 of about 50 nm to about 200 nm, wherein theparticle size distribution is described by a three-slice model in whicha certain percentage has an effective particle size by weight betweenabout 10 nm and about 100 nm, a certain percentage has an effectiveparticle size by weight between about 100 nm and about 200 nm, and acertain percentage has an effective particle size by weight above 200nm, and further wherein the three-slice model is identified as x %/y %/z%, respectively (e.g., 40%/30%/30%); (p) the neurosteroid has athree-slice distribution selected from the group 40%/30%/30%,50%/30%/20%, 60%/30%/10%, 40%/40%/20%, 50%/40%/10%, 70%/20%/10%,50%/45%/5%, 70%/25%/5%, 60%/35%/5%, 80%/15%/5%, 70%/30%/0%, 60%/40%/0%,90%/10%/0%, and 100%/0%/0%; (h) the neurosteroid is in the form ofparticles, wherein standard deviation of the particle size distributiondivided by the volume-weighted mean diameter is less than about 30%,less than about 25%, less than about 20%, less than about 15%, or lessthan about 10%. In alternative embodiments, the neurosteroid in thecomposition has at least two of the aforementioned properties; at leastabout three of the aforementioned properties; at least about four of theaforementioned properties; or at least five of the aforementionedproperties.

The neurosteroid nanoparticles may be prepared by grinding. Grinding cantake place in any suitable grinding mill. Suitable mills include an airjet mill, a roller mill, a ball mill, an attritor mill, a vibratorymill, a planetary mill, a sand mill and a bead mill. A high energy mediamill is preferred when small particles are desired. The mill can containa rotating shaft.

The preferred proportions of the grinding media, neurosteroid, theoptional liquid dispersion medium, and dispersing, wetting or otherparticle stabilizing agents present in the grinding vessel can varywithin wide limits and depends, for example, the size and density of thegrinding media, the type of mill selected, the time of milling, etc. Theprocess can be carried out in a continuous, batch or semi-batch mode. Inhigh energy media mills, it can be desirable to fill 80-95% of thevolume of the grinding chamber with grinding media. On the other hand,in roller mills, it frequently is desirable to leave the grinding vesselup to half filled with air, the remaining volume comprising the grindingmedia and the liquid dispersion media, if present. This permits acascading effect within the vessel on the rollers which permitsefficient grinding. However, when foaming is a problem during wetgrinding, the vessel can be completely filled with the liquid dispersionmedium or an anti-foaming agent may be added to the liquid dispersion.

The attrition time can vary widely and depends primarily upon the drug,mechanical means and the residence conditions selected, the initial anddesired final particle size, and so forth.

After attrition is completed, the grinding media is separated from themilled neurosteroid particulate product (in either a dry or liquiddispersion form) using conventional separation techniques, such as byfiltration, sieving through a mesh screen, and the like.

In one aspect, the grinding media comprises beads having a size rangingfrom 0.05-4 mm, preferably 0.1-0.4 mm. For example, high energy millingof neurosteroid with yttrium stabilized zirconium oxide 0.4 mm beads fora milling residence time of 25 minutes to 1.5 hours in recirculationmode at 2500 RPM. In another aspect the grinding media may be apolymeric milling media, which has the advantages of reduced heavingmetal contamination and is compatible with steam-in-place or autoclavesterilization/sanitation of the milling equipment and media. In anotherexample, high energy milling of neurosteroid with 0.1 mm zirconium oxideballs for a milling residence time of 2 hours in batch mode.Additionally, the milling temperatures, for certain of the disclosedembodiments, should not exceed 50° C. as the viscosity of the suspensionmay change. However, temperature limits are formulation specific. Hightemperature can exceed the cloud point of certain polymeric stabilizersand lead to agglomeration or viscosity increase. But, milling above 50°C. may be desirable for some formulations. The milling concentration isfrom about 1% to about 40% neurosteroid by weight. In one embodiment,the concentration is 25% neurosteroid by weight. In one embodiment, themilling media contains at least one agent to adjust viscosity so thatthe desired particles are suspended evenly, and a wetting and/ordispersing agent to coat the initial neurosteroid suspension so auniform feed rate may be applied in continuous milling mode. In anotherembodiment, batch milling mode is utilized with a milling mediacontaining at least one agent to adjust viscosity and/or provide awetting effect so that the neurosteroid is well dispersed amongst thegrinding media.

The disclosure provides methods of using injectable neurosteroidnanoparticle formulationscontaining the neurosteroid at a concentrationof about 0.25 mg/mL, about 0.5 mg/mL, about 1.0 mg/mL, about 1.5 mg/mL,about 2.0 mg/mL, about 2.5 mg/mL, about 3.0 mg/mL, about 3.5 mg/mL,about 4.0 mg/mL, about 4.5 mg/mL, about 5.0 mg/mL, about 5.5 mg/mL,about 6.0 mg/mL, about 6.5 mg/mL, about 7.0 mg/mL, about 7.5 mg/mL,about 8.0 mg/mL, about 8.5 mg/mL, about 9.0 mg/mL, about 10 mg/mL, about11 mg/mL, about 12 mg/mL, about 13 mg/mL, or about 15 mg/mL, about 30mg/mL, about 40 mg/mL, about 50 mg, mL, about 75 mg/ mL, or about 100mg/mL. All ranges including any two of the foregoing concentrations ofneurosteroid as endpoints are also included in the disclosure. Forexample, the disclosure includes neurosteroid nanoparticle formulationscontaining from about 0.5mg/mL to about 15 mg/mL, about 1.0 mg/mL toabout 10 mg/mL, about 2.0 mg/mL to about 8.0 mg/mL, or about 4.0 mg/mLto about 8.0 mg/mL, about 1.0 mg/mL to about 100 mg/mL, about 10 mg/mLto about 100 mg/mL, or about 30 mg/mL to about 50 mg/ mL neurosteroid.

Methods of Treatment

Methods of treatment include treating a patient suffering frompostpartum depression, premenstrual dysphoric disorder, menopausaldepression, or delirium tremens by administering the injectableneurosteroid formulation as a single dose (bolus dose), a series ofbolus doses, a continuous infusion, or a combination of one or morebolus doses and a continuous infusion. In certain embodiments theinjectable neurosteroid formulation of the disclosure is administeredintramuscularly or intravenously.

Administration of the injectable neurosteroid formulation may befollowed by oral administration of the neurosteroid.

The single bolus dose of any formulation of this disclosure may be aninjection and may be administered intramuscularly or intravenously. Thedose of the single injection may be from about 1 mg/kg to about 20mg/kg, from about 2 mg/kg to about 15 mg/kg, from about 2 mg/kg to about10 mg/kg, or about 2 mg/kg to about 8 mg/kg. Methods of treatment alsoinclude administering multiple injections of the disclosed formulationsover a period of 1 to 10 days. The injections may be given at intervalsof 1 to 24 hours. Dosing schedules in which the injectable formulationis injected every 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 12 hours,or 24 hours are included herein. Dosing schedules in which theinjectable formulation is injected for 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10days are included herein.

Methods of treatment include treating a patient suffering frompostpartum depression, premenstrual dysphoric disorder, menopausaldepression, or delirium tremens by administering one or more bolus dosesover a period of 10 days as described in the preceding paragraph of aninjectable formulation of this disclosure followed by an intravenousinfusion of the injectable formulation. In certain embodiments the bolusdose is administered over a period of about 1 to about 60, 1 to about30. about 1 to about 15, about 1 to about 10, or about 1 to about 5, orabout 5 minutes followed by commencement of the intravenous infusionwithin 1, 2, 3, 4, or 5 hours.

In some embodiments, an injectable formulation of this disclosure isadministered as an intravenous infusion dose, either without or withouta previous bolus dose for 1, 2, 3, 4. 5, 6, 7, 8, 9, or 10 consecutivedays. The infusion. dose may be administered at a rate of 1, 2, 3, 4, 5,6, 7, 8, 9, or 10 mg/kg/hr or in a range of about 1 mg/kg/hr to about 10mg/kg/hr or 2 mg/kg/hr to about 8 mg/kg/hrs.

In some embodiments the infusion dose (whether administered with orwithout the bolus dose) is followed by a first step down dosage, andoptionally a second step down dosage, an optionally a third step downinfusion dosage. In some embodiments, the first step dose is 95%, 90%,85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%,15%, 10%, or 5% of the infusion dose. In some embodiments, the firststep dose is between 95-50%, 75-50%, 85-50%, 90-50%, 80-50%, or 75-100%of the infusion dose. In an embodiment, the first step dose is 75% ofthe infusion dose. In some embodiments, the second step dose is 95%,90%, 85%, 80%, 75%, 70%, 65%, 60%. 55%, 50%, 45%, 40%, 35%, 30%, 25%,20%, 15%, 10%, or 5% of the first step down dose. In some embodiments,the second step dose is between 95-30%, 75-30%, 85-30%, 60-30%, 70-30%,50-30%, or 50-40% of the first step down dose. In an embodiment, thesecond step dose is 50% of the infusion dose. In some embodiments, thethird step dose is 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%,45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, or 5% of the second infusiondose. In some embodiments, the third step dose is between 50-5%, 40-5%,30-5%, 25-5%, 25-10%, 25-20%, or 25-40% of the second step down dose. Inan embodiment, the third step down dose is 25% of the infusion dose.

The disclosure includes methods of treating a patient suffering frompostpartum depression, premenstrual dysphoric disorder, menopausaldepression, or delirium tremens administering an effective amount aninjectable neurosteroid formulation of this disclosure to a patientwherein the amount of neurosteroid, e.g. ganaxolone, administered isfrom about 0.1 mg/kg to about 200 mg/kg.

The disclosure includes embodiments in which the injectable neurosteroidformulation is a ganaxolone formulation and is administered as a singlebolus dose of the ganaxolone formulation to the patient. In certainembodiments the single bolus dose provides a sufficient amount ofganaxolone to provide a plasma C_(max) of ganaxolone of about 20 ng/ mLto about 1000 ng/ mL in the patient. The disclosure includes a method oftreating postpartum depression in which the bolus dose provides a plasmaC_(max) of ganaxolone of 60 ng/ml.

The disclosure includes embodiments in which the injectable neurosteroidformulation is a ganaxolone formulation and is administered as a bolusdose and the bolus dose provides a sufficient amount of ganaxolone toprovide a plasma C_(max) of ganaxolone of about 20 ng/mL to about 900ng/mL in the patient.

The disclosure includes embodiments in which the injectable neurosteroidformulation is a ganaxolone formulation and is administered as a bolusdose and the bolus dose is administered in less than 10 minutes and theC_(max) occurs within 1 hour of completion of administration.

The disclosure includes embodiments in which the injectable neurosteroidformulation is a ganaxolone formulation is administered as a singlebolus dose and the single bolus dose comprises from about 0.1 mg/kg toabout 20 mg/kg ganaxolone. Or, optionally the single bolus dosecomprises from about 0.5 mg/kg to about 15 mg/kg ganaxolone, or about0.5 mg/kg to about 10 mg/kg ganaxolone, or from about 1 mg/kg to about30 mg/kg ganaxolone.

The disclosure includes embodiments in which multiple bolus doses of theinjectable neurosteroid formulation are administered to the patient. Incertain embodiments the multiple bolus doses are given over 1 to 10 daysat intervals of 1 to 24 hours. In certain embodiments the injectableneurosteroid formulation is a ganaxolone formulation and each bolus doseprovides a sufficient amount of ganaxolone to produce a plasma C_(max)of ganaxolone of about 20 ng/mL to about 1000 ng/mL in the patient. Incertain embodiments the interval between bolus doses is from about 10 toabout 24 hours and once an initial C_(max) is reached the plasmaconcentration of ganaxolone is not below 20 ng/mL at any time betweenbolus doses. In certain embodiments the interval between bolus doses is20 to 24 hours and once an initial C_(max) is reached and theconcentration of ganaxolone in the patient's plasma does not fall below25% of the initial C_(max) . In certain embodiment each bolus dosecomprises about 0.1 mg/kg to about 20 mg/kg ganaxolone. Or, optionallythe single bolus dose comprises from about 0.5 mg/kg to about 15 mg/kgganaxolone, or about 0.5 mg/kg to about 10 mg/kg ganaxolone, or fromabout 1 mg/kg to about 30 mg/kg ganaxolone.

In certain embodiments the method comprises administering an infusion ofthe injectable neurosteroid formulation to the patient, with or withoutan initial bolus dose. In certain embodiments the infusion isadministered for 1 to 10 consecutive days at a rate of 0.5 to 10mg/kg/hr without an initial bolus dose.

In certain embodiments the injectable neurosteroid formulation is aganaxolone formulation and the method comprises administering an initialbolus dose of the ganaxolone formulation comprising from about 0.1 mg/kgto about 20 mg/kg ganaxolone, followed within 24 hours by administrationof an infusion of the ganaxolone formulation for 1 to 10 consecutivedays at a rate of 0.5 to 10 mg/kg/hr.

In certain embodiments the injectable neurosteroid formulation is aganaxolone formulation and the method comprises administering an initialbolus dose of the formulation followed by an infusion dose, wherein theinitial bolus dose provides a sufficient amount of ganaxolone to providean initial plasma C_(max) of ganaxolone of about 20 ng/mL to about 1000ng/mL in the patient and the concentration of ganaxolone in thepatient's plasma does not fall below 25% of the initial C_(max) untilafter the subsequent infusion dosing is concluded. The disclosureincludes a method of treating postpartum depression in which theinfusion provides a plasma C_(max) of ganaxolone of 60 ng/ml. Thedisclosure also includes a method of treating postpartum depression inwhich the infusion provides a steady state plasma concentration of 20ng/ml to 100 ng/ml, or 40 ng/ml to 80 ng/ml, or at least 60 ng/ml.

In certain embodiments the injectable neurosteroid formulation is aganaxolone formulation and the method comprises administering an initialbolus dose of the ganaxolone formulation, wherein the initial bolus doseprovides a sufficient amount of ganaxolone to provide an initial plasmaC_(max) of ganaxolone of about 20 ng/mL to about 1000 ng/mL in thepatient, the patient is then administered an infusion of the ganaxoloneformulation at a constant dose sufficient to provide a concentration ofganaxolone in the patient's plasma of at least 40% of C_(max,) followedby an infusion of ganaxolone at a gradually reducing dose so that theconcentration of ganaxolone in the patient's plasma is less than 20% ofC_(max) when the infusion is concluded.

Combination Treatment

The disclosure includes embodiments in which the neurosteroid is theonly active agent and embodiments in which ganaxolone is administered incombination with one or more additional active agents. When used incombination with an additional active agent ganaxolone and theadditional active agent may be combined in the same formulation or maybe administered separately. Ganaxolone may be administered while theadditional active agent is being administered (concurrentadministration) or may be administered before or after the additionalactive agent is administered (sequential administration).

The disclosure includes methods of treating delirium tremens in whichthe additional active agent is an anti-convulsant or an anxiolytic.Anticonvulsants and anxiolytics include GABA_(A) receptor modulators,sodium channel blocker, GAT-1 GABA transporter modulators, GABAtransaminase modulators, voltage-gated calcium channel blockers,glutamate receptor modulators, and peroxisome proliferator-activatedalpha modulators.

The disclosure includes methods of treating delirium tremens in whichthe patient is given an anesthetic or sedative in combination withganaxolone. The anesthetic or sedative may be administered at aconcentration sufficient to cause the patient to lose consciousness,such as a concentration sufficient to medically induce coma or aconcentration effective to induce general anesthesia. Or the anestheticor sedative may be given at a lower dose effective for slight sedation,but not sufficient to induce a loss of consciousness.

A medically induced coma occurs when a patient is administered a dose ofan anesthetic, such as propofol, pentobarbital or thiopental, to cause atemporary coma or a deep state of unconsciousness. General anesthesia isa treatment with certain medications to cause unconsciousness sufficientto be unaware of pain during surgery. Drugs used for medically inducedcoma or general anesthesia include inhalational anesthetics andintravenous anesthetics which include barbiturate and non-barbiturateanesthetics.

Inhalational anesthetics include desflurane, enflurane, ethyl chloride,halothane, isoflurane, methoxyflurane, sevoflurane, andtrichloroethylene.

Intravenous, non-barbiturate anesthetics include atracurium,cisatracurium, etodimidate, ketamine, propofol, and rocuronium,

Barbiturates include amobarbital, methohexital, pentobarbital,phenobarbital, secobarbital, thiamylal, and thiopental.

Benzodiazepines are used both as anticonvulsants, anxiolytics andanesthetics. Benzodiazepines useful as anaesthetics include diazepam,flunitrazepam, lorazepam, and midazolam.

The disclosure includes administering propofol to induce anesthesia incombination with ganaxolone. Propofol is administered at a dose range ordosage range of 0.5- 50 mg/kg. Anesthesia is induced with an initialbolus of 10-50 mg/kg followed by additional intermittent boluses or10-50 mg/kg to maintain anesthesia. Anesthesia may also be maintained byan infusion of 3-18 mg/kg/min propofol.

The disclosure includes administering pentobarbital sodium byintravenous or intramuscular injection to induce anesthesia incombination with ganaxolone. Pentobarbital may be administered to adultsas a single 100-500 mg, or 100-200 mg intramuscular or intravenousinjection, or to pediatric patients as a single 2 to 6 mg/kg IM or IVinjection. Pentobarbital may be administered at a high dose to inducecoma in a delirium tremens patient and ganaxolone may then be given incombination with the pentobarbital to treat refractory seizures ofdelirium tremens. Pentobarbital doses used to induce coma include, aloading dose of 5 to 15 mg/kg or 10 to 35 mg/kg, given over 1-2 hoursfollowed by a maintenance dose of 1 mg/kg/hr to 5 mg/kg/hr for 12 to 48hours and tapering by 0.25 to 0.5 mg/kg/hr every 12 hours once seizureshave stopped.

The disclosure includes administering thiopental sodium in combinationwith ganaxolone. Thiopental can be administered as a 3 to 5 mg/kg bolusfollowed by additional boluses of 1 to 2 mg/kg every 3 to 5 minutesuntil seizures have stopped, to a maximum total dose of 10 mg/kg. Afterthe 10 mg/kg maximum bolus dose of thiopental has been reached,thiopental can be infused at 3 to 5 mg/kg/hr.

The disclosure includes administering midazolam in combination withganaxolone. Midazolam can be administered as a 0.5 mg/kg to 5 mg/kgloading dose, followed by a 1 to 5 microgram/kg/hour infusion.

In each embodiment in which an additional active agent is administeredto induce coma, anesthesia, or sedation, ganaxolone is administered asan injectable neurosteroid formulation and is administeredsimultaneously or sequentially with the additional active agent and isadministered according to any of the dosing schedules set forth hereinfor ganaxolone administration.

The injectable neurosteroid ganaxolone formulation of this disclosuremay be administered to a delirium tremens patient with another activeagent. Active agents for use in include a number of drug classes andoverlap to a certain extent with the coma-inducing, anesthetic, andsedative drugs that may be used in combination with ganaxolone. Activeagents that may be used in combination with the injectable neurosteroidformulation of this disclosure include aldehydes, such as paraldehyde;aromatic allylic alcohols, such as stiripentol; barbiturates, includingthose listed above, as well as methylphenobarbital and barbexaclone;benzodiazepines include alprazolam, bretazenil, bromazepam, brotizolam,chloridazepoxide, cinolazepam, clonazepam, chorazepate, clopazam,clotiazepam, cloxazolam, delorazepam, diazepam, estazolam, etizolam,ethyl loflazepate, flunitrazepam, flurazepam, flutoprazepam, halazepam,ketazolam, loprazolam, lorazepam, lormetazepam, medazepam, midazolam,nimetazepam, nitrazepam, nordazepam, oxazepam, phenenazepam, pinazepam,prazepam, premazepam, pyrazolam, quazepam, temazepam, tatrazepam, andtriazolam; bromides, such as as potassium bromide; carboxamides, suchcarbamazepine, oxcarbazepine, and eslicarbazepine acetate; fatty acids,such as valproic acid, sodium valproate and divalproex sodium; fructosedervivatives, such as toprimate; GABA analogs such as gabapentin andpregabalin, hydantoins, such as ethotoin, phenytoin, mephenytoin, andfosphenytoin; other neurosteroids, such as allopregnanolone,oxasolidinediones, such as paramethadione, trimethadione, and ethadione,propionates such as beclamide; pyrimidinediones such as primidone,pyrrolidines such as brivaracetam, levetiracetam, and seletracetam,succinimides, such as ethosuximide, pensuximide, and mesuximide;sulfonamides such as acetazoloamide sultiame, methazolamide, andzonisamide; triazines such as lamotrigine, ureas such as pheneturide andphenacemide; NMDA antagonists such as felbamate, and valproylamides suchas valpromide and valnoctamide; and perampanel.

This disclosure includes methods of treating postpartum depression,PMDD, or postmenopausal depression, in which the neurosteroid, e.g.ganaxalone is administered together with one or more non-neurosteroidalantidepressant. For example the non-neurosteroidal anti-depressant maybe a selective serotonin reuptake inhibitor such as citalopram,escitalopram, femoxetine, fluoxetine, fluvoxamine, paroxetine,sertraline, or zimeldine; a serotonin partial agonist such as pindolol,gepirone, or flesinoxan; a selective serotonin norepinephrine reuptakesuch as duloxetine, venlafaxine, desvenlafaxine, milnacipran, orclovoxamine; a norepephrine reuptake inhibitor such as atomoxetine andreboxetine; a serotonin-2 antagonist reuptake inhibitor such astrazodone; and alpha-2 antagonist/serotonin 5HT2-3 receptor antagonistsuch as mirtazapine; a norepinephrine dopamine reuptake inhibitors suchas bupropion, or a tricyclic antidepressants include, but are notlimited to, doxepin, amitriptyline, amoxapine, clomipramine,desipramine, doxepin, imipramine, maprotiline, nortriptyline,protriptyline, and trimipramine.

The disclosure also includes methods of treating PPD in women withbipolar disorder. Methods of treating bipolar depression or PPD in womenwith biopolar disorder include administering an oral dose of ganaxolone.The total oral daily dose for treating PPD in women with bipolardisorder is from 50 mg to 2000 mg ganaxolone, administered as a singledaily dose or twice daily. In other embodiments the total ganaxolonedaily dose is 200 mg to 1500 mg, 300 mg to 1200 mg, or 300 mg to 900 mg,or 600 mg, administered in a single daily dose or two doses. In someembodiments ganaxolone is administered together with another activeagent used for the treatment of bipolar depression such as lithium,lamotrigine, quetiapine, olanzapine, valproate, carbamazepine, andlurasidone. In certain embodiments a patient suffering from bipolardepression may first be treated with an injectable neurosteroid, such asand intravenous ganaxolone infusion for 1-5 days, and then switched tooral ganaxolone.

Method of treating postpartum depression, PMDD, or postmenopausaldepression include administering an injectable neurosteroid formulation,such as an injectable ganaxolone formulation, to the patient as a singlebolus dose, multiple bolus doses given over a period of 1 hour toseveral days, or as an intravenous infusion administered from 6 hours to96 hours followed by maintenance administration of a ganaxolone oralformulation. Methods of treating postpartum depression includeadministering an oral dose of ganaxolone daily beginning in the lutealphase of the menstrual cycle, or at day 18-24 of the menstrual cyclesuntil day 2-4 of the menstrual cycle. The total oral daily dose is from100 mg to 2000 mg ganaxolone, administered as a single daily dose ortwice daily. In other embodiments the total ganaxolone daily dose is 200mg to 1500 mg, 300 mg to 1200 mg, or 300 mg to 900 mg, or 600 mg,administered in a single daily dose or two doses. Ganaxolone oralformulations have been previously disclosed, for example in U.S. Pat.Nos. 9,056,116, 9,029,355, 8,618,087, 8,318,714, 8,022,054, and U.S.Pat. No. 7,858,609, each of which is incorporated by reference for itsteachings regarding oral ganaxolone formulations.

Specific Embodiments

In a first embodiment the disclosure provides a method of treating apatient having postpartum depression, premenstrual dysphoric disorder,menopausal depression, or delirium tremens comprising administering aneffective amount of an neurosteroid formulation to the patient; whereinthe neurosteroid formulation is an ganaxolone formulation.

In an embodiment the ganaxalone formulation is an intravenousformulation.

In an embodiment wherein the intravenous ganaxolone formulationcomprises

a) water; b) sulfobutyl ether-β-cyclodextrin (CAPTISOL) and ganxalone,wherein the ratio of sulfobutyl ether-β-cyclodextrin to ganaxolonewherein weight to weight (w/w) ratio of sulfobutyl ether-β-cyclodextrinis about 52:1 or greater; and c) a buffer, the formulation having a pHof 6.8 to 7.6. The intravenous ganaxolone formulation of this embodimentmay additionally comprise 0.5% to 1.5% weight percent sodium chloride;and 0.5% to 15% weight percent surfactant, wherein the surfactant isselected from the group consisting of a sorbitan ester, apolyoxyethylene sorbitan fatty acid ester, a poloxamer, a cholesterolsalt, or a bile salt.

In any of the previous embodiments formulation comprises 0.1 mg/mL to 15mg/mL ganaxolone and 5.5 mg/mL to 800 mg/ml sulfobutylether-β-cyclodextrin.

In any of the previous embodiments the formulation additionallycomprises a preservative, and the preservative is benzyl alcohol,chlorbutanol, 2-ethoxyethanol, parabens (including methyl, ethyl,propyl, butyl, and combinations), benzoic acid, sorbic acid,chlorhexidene, phenol. 3-cresol, thimerosal, or a phenylmercurate salt.

The disclosure also provides a method of treating a patient havingpostpartum depression, premenstrual dysphoric disorder, menopausaldepression, or delirium tremens comprising administering an effectiveamount of an injectable neurosteroid formulation to the patient; whereinthe formulation comprises

a neurosteroid selected from allopregnanolone, ganaxolone, alphaxalone,alphadolone, hydroxydione, minaxolone, pregnanolone,tetrahydrocorticosterone, and combinations of the foregoing;

a surface stabilizer selected from hydroxyl ethyl starch, dextran, andpovidone; and a surfactant.

In certain embodiments in which the formulation comprises a surfacestabilizer, the neurosteroid is ganaxolone.

In certain embodiments in which the formulation comprises a surfacestabilizer, the neurosteroid is allopregnanolone.

In certain embodiments in which the formulation comprises a surfacestabilizer, the surface stabilizer is hydroxyethyl starch.

In certain embodiments in which the formulation comprises a surfacestabilizer, the surface stabilizer is sodium cholate, sodiumdeoxycholate, or sodium cholesterol sulfate.

In certain embodiments in which the formulation comprises a surfacestabilizer, wherein the (wt:wt) ratio of the neurosteroid to the surfacestabilizer is about 4:1 to about 3:1.

In certain embodiments in which the formulation comprises a surfacestabilizer,

the nanoparticles have a D50 of 10 nm to 300 nm;

the formulation additionally comprises 0.5% to 1.5% weight percentsodium chloride;

the formulation additionally comprises a buffer and a preservativeselected from benzyl alcohol, chlorbutanol, 2-ethoxyethanol, parabens(including methyl, ethyl, propyl, butyl, and combinations), benzoicacid, sorbic acid, chlorhexidene, phenol, 3-cresol, thimerosal,phenylmercurate salt, and combinations of the foregoing.

In any preceding embodiment the patient can be administered 0.1 mg/kg to200 mg/kg neurosteroid as a single bolus dose. The single bolus dose canbe a bolus dose can provide a sufficient amount of ganaxolone to providea plasma C_(max) of ganaxolone of at least 60 ng/mL in the patient.

In any preceding embodiment the patient can be administered theformulation as an intravenous infusion for 1 hour to 10 consecutive daysat a rate of 1 to 10 mg neurosteroid/hr/kg, with or without an initialbolus dose.

In any embodiment in which the neurosteroid is an injectableneurosteroid formulation, the formulation can be administered to thepatient as a ganaxolone infusion administered at the rate of 2 mg/hr to4 mg/hr.

In any preceding embodiment the injectable neurosteroid formulationadministered to the patient is a ganaxolone infusion administered at arate sufficient to provide a steady state plasma concentration of 50ng/ml to 100 ng/ml. In certain embodiments the ganaxolone infusion isadministered at for 36 hrs to 72 hrs.

The disclosure includes a method of treating a patient, wherein thepatient is a patient having premenstrual dysphoric disorder and thepatient is administered a daily oral dose of ganaxolone of 100 mg to2000 mg administered from day 18-24 of the patients menstrual cyclesuntil day 2-4 of the patient's menstrual cycle.

The disclosure includes a method of treating a patient, wherein thepatient is a patient having menopausal depression and the patient isadministered a daily oral dose of ganaxolone of 100 mg to 2000 mgganaxolone.

The disclosure includes a method of treating a patient, wherein thepatient is a patient having postpartum depression, premenstrualdysphoric disorder, or menopausal depression, and the patient isadministered the ganaxolone in combination with an SSRI or SNRIantidepressant.

The disclosure includes a method of treating a patient, wherein thepatient is a patient having delirium tremens and the patient isadministered a ganaxolone intravenous infusion at a rate of 50 mg/hr to500 mg/hr for 1 to 5 days. In this embodiment the patient may beadministered the ganaxolone in combination with an intravenousbenzodiazepine infusion.

EXAMPLES Example 1 Preparation of Injectable Ganaxolone Formulation

Ganaxolone solubility in aqueous CAPTISOL solution was first determinedby constructing a phase solubility diagram. Excess ganaxolone was shakenin aqueous CAPTISOL solutions of known concentrations for 42 hours toreach equilibrium. The ganaxolone solution was filtered into HPLC vialsthrough 0.45 μm syringe filters. The filtrates were assayed forganaxolone concentration by HPLC. The results are summarized in Table 1.Moles of ganaxolone in solution against moles of CAPTISOL added wereplotted. Ganaxolone solubility in water was found to increase linearlywith the addition of CAPTISOL indicating the formation of 1:1 complexbetween ganaxolone and CAPTISOL. A plot of weight (mg) of ganaxolone insolution against weight (mg) of CAPTISOL added (FIG. 1), shows theweight: weight ratio of CAPTISOL to ganaxolone required for ganaxolonesolubilization at equilibrium to be approximately 52:1.

TABLE 1 CAPTISOL CAPTISOL Ganaxolone Ganaxolone conc. conc. conc. byconc. No. (mg/mL) (M) HPLC (mg/mL) (M) 1 400 0.185 7.68 0.0231 2 2000.0925 3.63 0.0109 3 100 0.0462 1.86 0.0056 4 50 0.0231 0.88 0.0027 5 250.0116 0.43 0.0013 6 0 0 Not detectable 0

To prepare injectable solutions, excess ganaxolone is added to anaqueous 400 mg/mL CAPTISOL solution. The solution is shaken at leastovernight and filtered through a 0.45 micron filter. Ganaxoloneconcentration of the filtered solution is determined by HPLC. Theganaxolone/ CAPTISOL solution (7.68 mg/mL in 400 mg/mL aqueous CAPTISOL)is diluted in saline to obtain 3.84 mg/mL, 0.77 mg/mL and 0.39 mg/mLganaxolone solutions in 0.9% saline. All solutions were clear and freefrom any visible precipitation. The ganaxolone solutions remained freeof any visible precipitation after freezing and thawing.

Example 2 Preparation of Injectable Ganaxolone-CAPTISOL Solution (5MG/ML)

Ganaxolone (0.50 g) was first mixed manually using a spatula with asmall amount (approximately 20 mL) of 30% w/v CAPTISOL solution insterile water for injection to form a uniform paste. Additional amount(approximately 40 mL) of 30% w/v CAPTISOL solution was then added toobtain a slurry. The suspension was stirred using a magnetic stir barfor 20 minutes. It was sonicated using a probe sonicator for 2 hours.While sonicating, an additional 30% w/v CAPTISOL solution was addeduntil total amount of the CAPTISOL solution reached 99.58 mL. Thestirred formulation was then heated at 68.5° C. for about 2.5 hours toobtain a solution. Heat was removed and the solution was stirred at roomtemperature for approximately 2 hours. Volume lost due to evaporationwas replenished with water. The clear solution was sterile filteredthrough 0.2 μm Nylon membrane filter.

Example 3 Buffered Ganaxolone-CAPTISOL Solutions

Monobasic potassium phosphate (19.6 mg) and dibasic sodium phosphateheptahydrate (93.3 mg) were added to 3 mg/mL ganaxolone solution in 30%Captisol (20 mL) with an initial pH 4.53. The mixture was sonicated for1 minute to obtain a clear solution having pH 6.95. About 10 mL of thissolution was maintained at 80° C. with magnetic stirring alongside theunbuffered control in closed glass vials. The remaining 10 mL of thesample was kept at 5 ° C. as control. Aliquots were taken at 67 hoursand 5 days. The samples were analyzed by HPLC and results are shown inTable 2.

TABLE 2 Stability of unbuffered and phosphate bufferedganaxolone/Captisol solution after 5 days at 80° C. Stability ofBuffered Ganaxolone Solutions 5 days at 5° C. 67 h at 80° C. 5 days at80° C. Phosphate Phosphate Phosphate Degradation Buffered bufferedBuffered product Unbuffered PH 6.95 Unbuffered pH 6.95 Unbuffered PH6.95 3-Epimer of ND ND 0.64% ND 1.89% 0.03% ganaxolone 17-Epimer of NDND 0.13% 0.07% 0.39% 0.13% ganaxolone ND, Not detected

Example 4 Injectable Ganaxolone- 30% CAPTISOL Solution ContainingPolysorbate 80

500 μl of 10% aqueous Polysorbate 80 solution in a 20 ml scintillationvial were combined with powdered ganaxolone (50 mg). The mixture wasstirred to wet the ganaxolone. Solid Captisol (3.2 g), sufficient toform a 30% Captisol solution, was then added to the vial and the vialcontents were mixed. Deionized water (8.0 g) was then added and themixture was vigorously stirred at room temperature overnight to obtain ahazy solution. An aliquot was filtered through 0.2 μm syringe filter andganaxolone concentration was assayed by HPLC to be 4.28 mg/ml.

The following injectable ganaxolone-30% Captisol solutions were preparedby the methods of this example.

(a) Ganaxolone-30% Captisol solution containing ethanol.

Ganaxolone was vigorously stirred in 30% Captisol in the presence of 10%v/v ethanol overnight to obtain a 3.16 mg/ml ganaxolone solution.

(b) Ganaxolone-30% Captisol solution containing glycerin

Ganaxolone was vigorously stirred in 30% Captisol in the presence of 10%v/v glycerin overnight to obtain a 3.45 mg/ml ganaxolone solution.

(c) Ganaxolone-30% Captisol solution containing propylene glycol

Ganaxolone was vigorously stirred in 30% Captisol in the presence of 10%v/v propylene glycol overnight to obtain a 2.53 mg/ ml ganaxolonesolution.

Example 5 Preparation of ganaxolone/30% CAPTISOL Solution by Prior DryMixing of Ganaxolone and CAPTISOL

Powdered ganaxolone (125 mg) was charged into 100 ml beaker. Captisolpowder (7.9 g) was then added to the beaker. The mixture was mixed bystirring with a magnetic stir bar for 5 minutes. Deionized water (20.1g) was weighed into a plastic cup. About half of the water was addedinto the beaker and the contents were vigorously stirred for 30 minutesto obtain a homogeneous mixture. The remaining water was added and thebeaker was covered with paraffin film. The contents were stirredvigorously at room temperature overnight to obtain a 4.61 mg/ mlganaxolone solution. After 90 hours of stirring, the ganaxoloneconcentration remained unchanged.

Example 6 Preparation of Ganaxolone Nanosuspension (10% WT) Via Wet BeadMilling

An aqueous slurry (250 g) containing ganaxolone (25g), hydroxyethylstarch (7.5g), sodium deoxycholate (0.5g) and 30% simethicone (1 drop)was milled using a Netzsch Mill (Minicer) with 0.3 mm YTZ beads (Yttriumstabilized grinding media, Tosoh Corporation, Japan, ZrO₂+HfO₂ (95 wt %(weight %)), Y202 (5 wt %)). Two additional portions of solid sodiumdeoxycholate (0.5g each) were added at 100 and 130 minutes after millinghad started. The particle size of the milled slurry was measured using aHoriba LA-910 laser diffraction particle size analyzer. After 170minutes of milling, D50 was 192 nm (188 nm after 1 min sonication). Atthis point, milling was stopped and the milled slurry was kept at roomtemperature overnight. The next morning, milling was resumed until thetotal milling time had reached 320 minutes, at which point D50 was 167nm (169 nm after 1 minute sonication). The D50 particle size wasmeasured on a Horiba 910 Laser Light Scattering instrument.

Example 7 Preparation of Ganaxolone Nanosuspension (20% WT) Via Wet BeadMilling

An aqueous slurry (250 g) containing ganaxolone (50 g), hydroxyethylstarch (15 g), sodium deoxycholate (3 g) and 30% simethicone (0.15 g)was milled using a Netzsch mill (Minicer) with 0.3 mm YTZ beads for 240minutes. The D50 of the milled slurry was 189 nm (185 nm after 1 minutesonication).

Example 8 Preparation of Ganaxolone Nanosuspension (20% WT) Via Wet BeadMilling Using 0.2 mm YTZ Beads

An aqueous ganaxolone slurry having the same composition as described inExample 2 was milled using a Netzsch mill (Minicer) with 0.2 mm YTZbeads for 245 minutes. The D50 was 172 nm (167 nm after 1 minutesonication).

Example 9 Preparation of Ganaxolone Nanosuspension Containing Dextran 70Via Wet Bead Milling

An aqueous ganaxolone slurry (250 g) containing ganaxolone (25 g),dextran 70 (7.5 g), sodium deoxycholate (1.5 g), and 30% simethicone(0.075 g) was milled using a Netzsch mill (Minicer) with 0.2 mm YTZbeads for 195 minutes to obtain a ganaxolone nanosuspension with D50 of159 nm (158 nm after 1 minute sonication). Prolonged milling causedparticle size to increase to 215 nm (212 nm after 1 minute sonication).

Example 10 Preparation of Ganaxolone Nanosuspension Containing 10%Hydroxyethyl Starch

An aqueous ganaxolone suspension (250 g) containing ganaxolone (25 g),hydroxyethyl starch (25 g), sodium deoxycholate (3 g) and 30%simethicone (0.15 g) was milled using a Netzsch mill (Minicer) with 0.2mm YTZ beads for 150 minutes to obtain a ganaxolone nanosuspension withD50 value of 139 nm (140 nm after 1 minute sonication).

Example 11 Dilution of Ganaxolone Nanosuspension Concentrate and SterileFiltration Through 0.2 Micron Filter

The ganaxolone nanosuspension of Example 10 was diluted 5-fold with HPLCgrade water to obtain a nanosuspension containing about 20 mg/mLganaxolone. This suspension was filtered through a 0.2 μm syringe filter(Cellulose acetate, 25 mm, 0.2 μm, product #: 13-250020-25 PK,Scientific Strategies). The particle size of the filtered ganaxolonesuspension was measured and found to be: D50, 143 nm (143 nm after 1minute sonication); D90, 219 nm; D95, 289 nm.

Example 12 Ganaxolone Nanosuspension Containing Poloxamer 188

A KDL Bachofen Mill was configured with the batch chamber attachment(approx. 350 ml) and the 96 mm polyurethane rotor attached to the shaft.Next, 265 ml of 0.3 mm ytria-zirconia beads were added dry to thechamber, followed by 176.7 gm of the Ganaxolone (GNX) slurry. Slowly,over 15 minutes, the ganaxolone slurry was added to the milling mediacontaining Pluronic F-68 (Poloxamer 188) with sustained stirring. Themixture was stirred slowly overnight. The slurry was milled at Speed 1(1500 rpm) with intermittent measurement of particle size. After 90minutes, the D50 particle size was determined to be 378 nm. The D50measurement was measured on a Horiba 910 Laser Light Scatteringinstrument.

Milling Media Pluronic F-68 27.0 g Sodium deoxycholate 2.7 g Simethiconeemulsion 30% 0.2 g Water (DI) to 200 g Ganaxolone Slurry Ganaxolone 50 gMilling Media 150 g Final Milling Composition (wt %) Ganaxolone 25%Pluronic F-68 10% Deoxycholate 1%

Example 13 Ganaxolone Nanosuspension Containing Poloxamer 188, 0.1 MMBeads

The KDL Bachofen mill was configured with the batch chamber attachment(approx. 350 ml) and the 96 mm polyurethane rotor attached to the shaft.Next, 300 ml of 0.1 mm ytria-zirconia beads were added dry to thechamber, followed by 134.6 gm Ganaxolone (GNX) slurry having thecomposition given in preceding Example 9. The slurry was milled for 60minutes and the D50 particle size was measured after 20, 40, 60 minutesof milling.

Time (min) Particle size, μm After sonication, μm 20 0.182 0.183 400.164 0.165 60 0.162

Example 14 Ganaxolone Nanosuspension Containing 12.5% Poloxamer 188 andDextran

The KDL Bachofen mill was configured with the batch chamber attachment(approx. 350 ml) and the 96 mm polyurethane rotor attached to the shaft.Next, 300 ml of 0.1 mm yttria-zirconia beads were added dry to thechamber, followed by 176.5 gm of the Ganaxolone (GNX) millingsuspension. The ganaxolone milling suspension was prepared by combiningthe dextran, Pluronic F-68, sodium deoxycholate, and simethiconeemulsion ingredients with stirring, and then adding the ganaxolone lastwith stirring. The suspension stirred for 1.5 hr. The suspension (176.5gm was added to the batch chamber and the mill started at Speedsetting 1. The slurry was milled for 60 minutes and the D50 particlesize was measured after 20, 40, 50, and 60 minutes of milling.

Ganaxolone Milling Suspension Dextran (40K mol. wt.) 10.0 g PluronicF-68 25.0 g Sodium deoxycholate 0.5 g Simethicone emulsion 30% 0.2 gGanaxolone 20.0 g Water (DI) to 200 g Final Milling Composition (wt %)Ganaxolone 20% Dextran  5% Pluronic F-68 25% Sodium Deoxycholate 0.25%  

Time (min) Particle size, μm After sonication, μm 20 0.221 0.219 400.173 — 50 0.166 0.168 60 0.164 —

The milled suspension above (64.4 gm) was treated with methyl paraben Na(0.074 gm and citric acid (0.027 gm) and the particle size monitoredover time.

Day Particle size, μm 0 0.191 2 0.194 5 0.313 6 0.317

Example 15 Treatment of Postpartum Depression With Injectable GanaxoloneCAPTISOL Formulation

An injectable ganaxolone/ Captisol formulation of example 4 containingPolysorbate 80 was used in this study. An injectable ganaxolonenanoparticle formulation containing a polymeric stabilizer, an ionicsurfactant such as sodium deoxycholoate, sucrose, and a buffer may alsobe used. Subjects are 18-45 year old females who experienced a MajorDepressive Episode in the postpartum period beginning during the lasttrimester or within the first 4 weeks following delivery, exhibit aHAM-D-17 score of 26 or greater, a Clinical Global Impression ofSeverity (CGI-S) score of 5 or greater; and were less than 6 monthspostpartum. All subjects have ceased lactating, or if still lactatinghave already fully and permanently weaned their infant; or if stillactively breastfeeding, patients agree to cease giving breast milk totheir infant prior to study entry. Five subjects are administered theganaxolone/ Captisol formulation as an intravenous infusion at a rate of3 mg/hr, which is considered sufficient to produce a steady stateganaxolone plasma concentration of 60 ng/ml. The infusion isadministered for 60 hours. The control group includes five subject whoare administered a placebo infusion of physiological saline, also for 60hours. Initiation of the infusion is considered T zero (T₀). Adepression symptom rating scale, either the HAM-D-17 or MADRS isadministered to all subjects periodically from T₀ to T₇₂ (within 72hours after starting the infusion) and then administered at least onceduring the 30 day post infusion follow-up period.

Example 16 Treatment of Premenstrual Dysphoric Disorder

The following study is a randomized, double-blind cross over trial. Tobe eligible participants must be between the ages of 21-46 and haveregular menstrual cycles. Eligible participants must meet the DSM 5criteria for PMDD. Eligible participants must have a definitive PMDDdiagnosis and also meet the daily rating severity of Problems (DRSP)criteria showing menstrual cyclicity of symptoms (see below).Participants will be required to maintain a daily menstrual calendar andmust be able and willing to use a non-hormonal method of birth control.

Eligible participants will be randomized to either ganaxolone or placebofor 2 menstrual cycles and then switched to the other condition for 2menstrual cycles. They will have a final assessment after they havecompleted charting and 4 cycles of double blind treatment. Treatmentwill be initiated in the middle of the luteal phase of the menstrualcycle and participants will be asked to stop taking pills short afterthe onset of menses.

At the initial visit the patient will be administered the StructuredClinical Interview for DSM-5. Eligible participants will have bloodcollected for a chemistry profile and a complete blood count and willprovide urine for a pregnancy and drug use test. The following efficacymeasures will be obtained: luteal phase symptom severity, with theluteal phase defined as the 7 days prior to the onset of menses for thisand subsequent visits, using the Premenstrual Tension Scale (PMTS), theInventory of Depressive Symptomatology (IDS-C) and the Clinical GlobalImpressions (CGI)-Severity scale. Health-related quality of life andfunctional impairment during the 7 days prior to the onset of menseswill be evaluated at this visit and every 2 to 4 months using theQuality of Life, Enjoyment and Satisfaction Questionnaire (Q-LES-Q).

This study is designed to show that replacement of decliningneurosteroid levels diminishes the symptoms of PMDD. Therefore eachparticipant should commence treatment around the progesterone peakduring the luteal phase of the menstrual cycle (˜Day 22) and continuetreatment until the peak symptomatic period that ends at Day 3 of thesubsequent menstrual cycle. Each participant will begin monitoringovulation the Day 10 of her menstrual cycle using an ovulationmonitoring kit, with day 1 being the first day of menses and continuemonitoring until the indicator shows that ovulation is imminent. Theparticipant will start pills days 10 days after the indicator ispositive for ovulation. Women will take pills from bottles that have amedication event monitoring cap (MEM cap) that tracks when the bottle isopened and hence capsules taken.

Dosing. Study participants will take oral ganaxolone on the followingschedule.

Day of Menstrual Cycle Day 22-26 Day 27-Day 2 Day 3-4 AM 1 cap 2 caps 1caps PM 1 cap 2 caps 1 caps Total Dose 600 mgs 1200 mgs 600 mgs

Treatment visits 2-4. Subjects will be seen for follow-up visitsapproximately 1-3 days after onset of menses in order to assess allluteal phase symptoms, side effects and possible discontinuationsymptoms. Cross over to the other condition will occur at Visit 3.Rating scales will be administered (PMTS, CGI-Severity and ImprovementScales, IDS-C).

Example 17 Treatment of Postmenopausal Depression

The following study is a randomized, double-blind trial. To be eligibleparticipants must be females over the age of 44 and have ceased havingmenses for at least one year. Eligible participants must meet the DSM 5criteria for MDD.

Eligible participants will be randomized to either treatment withganaxolone or placebo Participants will be administered a depressionsymptoms rating scale, either the HAM-D-17 or MADRS one week prior tothe study, at study commencement, and each week during the study. Studyparticipants in the experimental group will receive 2 doses oralganaxolone of 300 mg each, twice daily. Allopregnanolone levels of allsubjects will be measured throughout the study. The primary end-point inthis study will be change from baseline in HAM-D-17 or MADRS scoresbetween the placebo and ganaxolone arms. The duration of treatment willbe 12-weeks.

Example 18 Treatment of Alcohol-Withdrawal Delirium Tremens

Patients experiencing acute alcohol-withdrawal delirium tremens whoremain delirious and agitated despite treatment with standard of carebenzodiazepine regimen will be randomized to receive an add-onintravenous ganaxolone infusion or placebo infusion. The intravenousganaxolone dose will be from 50 mg/hr to 500 mg/hr and will beadministered for 1 to 5 days. Patients will be monitored for agitation,seizures, use of additional rescue benzodiazepines, vital signs andclearing of delirium. Patient's vital signs will be monitoredcontinuously during treatment. The study will be conducted in a medicalinpatient unit or ICU.

What is claimed is:
 1. A method of treating postpartum depression,premenstrual dysphoric disorder, menopausal depression, or deliriumtremens comprising administering an effective amount of an neurosteroidformulation to a patient in need thereof; wherein the neurosteroidformulation is an ganaxolone formulation comprising a) water; b)sulfobutyl ether-β-cyclodextrin (CAPTISOL) and ganaxalone, wherein theratio of sulfobutyl ether-β-cyclodextrin to ganaxolone wherein weight toweight (w/w) ratio of sulfobutyl ether-β-cyclodextrin is about 52:1 orgreater; and c) a buffer, the formulation having a pH of 6.8 to 7.6. 2.The method of claim 1 wherein the ganaxalone formulation is anintravenous formulation.
 3. The method of claim 1, wherein ulationcomprises 0.1 mg/mL to 15 mg/mL ganaxolone and 5.5 mg/ mL to 800 mg/mlsulfobutyl ether-β-cyclodextrin.
 4. The method of claim 2, wherein thepatient is administered 0.1 mg/kg to 200 mg/kg neurosteroid as a singlebolus dose.
 5. The method of claim 4, wherein the single bolus doseprovides a sufficient amount of ganaxolone to provide a plasma C_(max)of ganaxolone of at least 60 ng/ mL in the patient.
 6. The method ofclaim 2, wherein the patient is administered the formulation as anintravenous infusion for 1 hour to 10 consecutive days at a rate of 1 to10 mg neurosteroid/hr/kg, with or without an initial bolus dose.
 7. Themethod of claim 2, wherein the intravenous neurosteroid formulationadministered to the patient is a ganaxolone infusion administered at therate of 2 mg/hr to 4 mg/ hr.
 8. The method of claim 2, wherein theintravenous neurosteroid formulation administered to the patient is aganaxolone infusion administered at a rate sufficient to provide asteady state plasma concentration of 50 ng/ ml to 100 ng/ ml.
 9. Themethod of claim 7, wherein the intravenous neurosteroid formulation is aganaxolone formulation which is administered at for 36 hrs to 72 hrs.10. The method of claim 1, wherein the patient is a patient havingpremenstrual dysphoric disorder and the patient is administered a dailyoral dose of ganaxolone of 100 mg to 2000 mg administered from day 18-24of the patients menstrual cycles until day 2-4 of the patient'smenstrual cycle.
 11. The method of claim 1, wherein the patient is apatient having menopausal depression and the patient is administered adaily oral dose of ganaxolone of 100 mg to 2000 mg ganaxolone.
 12. Themethod of claim 11, wherein the patient is administered the ganaxolonein combination with an SSRI or SNRI antidepressant.
 13. The method ofclaim 1, wherein the patient is a patient having delirium tremens andthe patient is administered a ganaxolone intravenous infusion at a rateof 50 mg/ hr to 500 mg/hr for 1 to 5 days.
 14. The method of claim 13,wherein the patient is administered the ganaxolone in combination withan intravenous benzodiazepine infusion.